ПИТАНИЕ НЕКОТОРЫХ ВИДОВ РЫБ-ПОПУГАЕВ (SCARIDAE) НА БУРЫХ МАСЛЯНИСТЫХ КОРАЛЛОВЫХ ПЕСКАХ В ЗАЛИВЕ НЯЧАНГ (ЮЖНО-КИТАЙСКОЕ МОРЕ, ЦЕНТРАЛЬНЫЙ ВЬЕТНАМ)

Abstract

Two species of parrotfishes (Scaruspsittacus and S. rivulatus) were first observed feeding on brown coral sands during the food migration along the reef of Mun Island in the Nha Trang Bay. The most intensive feeding of these species on sands was recorded in the depth range of 8-10 m, although some specimens were fed up to a depth of 15 m. Benthic microphytic communities (microphytobenthos), abundantly developing on the surface of coral sand in the places of feeding of parrotfishes, give it a characteristic brown color. In the interval of depths of 8-10 m, there was a transition from upper sublittoral coenoses, formed mainly by small forms of diatoms, to coenoses of middle sublittoral, where the leading roles belonged to large species. In addition, large-trichome forms of cyanoprokaryotes were abundantly observed in all the studied communities. The oily nature of the spots is due to the release of a large number of neutral lipids from diatom cells, which die off as a result of high competition, since the density of microphytes development is very high here. Eating sand from such brown spots, parrot fish swallow it together with a huge number of diatoms and cyanobacteria, which are of significant nutritional value for them (fish feed on “salad” from microalgae, rich in diatom oil and cyanoprokaryote proteins).Thus, the zone of the most intensive feeding of parrotfishes on brown coral sands (8-10 m) is characterized by the greatest species and size diversity of microphytes and their high concentration.